The paper deals with storage and generation systems with renewable energy sources. A stand-alone combined system with electrochemical batteries, supercapacitors and fuel cells is considered. The power flow among the different storage devices is controlled in order to optimise the energetic efficiency and avoid irregular working conditions. A proper control strategy is proposed to keep constant the fuel cell power and limit the charge/discharge batteries current. The control strategy is implemented by means of two hierarchical algorithms on the power converters that interconnect storage devices and generation sources. Experimental tests done on electrical drives to validate the algorithm are illustrated and the results are discussed.